Waste-heat plant and method of operating the same



Nov 10, 1925- i J. BELL .wAs'iE any: PLANT AND METHOD OF OPERATING THESAME i md Deb. 2:5. 1922 2 Sheets-Sheet 1 Nov. 10 i 1925- J. E. BELLWASTE 'HEAT PLANT AND METHOD OF OPERATING-THE SAME Filed Dec 23 1922 2Sheets-Sheet 2 jwera ar afoiauzrfi el 12C ML;

Patented Nov. 10, 1925.

UNITED. STAT-Es;

worm E. BELL, or 3300mm, new You.

.was'm-nmr nan-r am) unrno'n' or ornmrme rnnsmn Application medDecember-23,1928. Serial No. 608,680..

' is a true and exact descriptiomreference being had to the accompanyingdrawings, which form apart thereof.

My invention relates to waste heat plants of the kind now commonlyemployed in connection with that form of industrial furnaces known asrotary kilns and in whichthe gases from the furnaces are delivered intoa common waste heat flue and drawn from said flue for heating aplurality of boilers by means'of draft fans. A common incident in theoperation of such a plant 'is the shutting down for cleaning, re airs orother purposes of one or more 0 a plurality of boilers and, as the draftfans are normally operated at close to their capacity,

the result of shutting down one or more boilers is that the fans stillinuse are not capable of handling all the gssesgiven off by the furnacesand the dra through the furnace is therefore diminished below the normaland effective amount. The pri mary object of my invention is to providefor maintaining a normal and proper draft in the common flue and throu hthe furnaces under all conditions whic are likel to occur and I do thisby providing an ad ditional gas outlet from the common flue andmaintainin in said outlet a suction or draft equal to t at normallyexisting'in the flue. My preferred construction for carrying out thispurpose is to provide, in connection with the additional outlet from theflue, a stack of such height that when filled with hot gases from theflue there will be produced a draft or suction at the bottom equal to,or greater than, that normally existing in the flue and of such capacitythat it will carry off such amount of superfluous gas as may be expectedto exist in the flue at any time owing to the shut-down of one or moreboilers. The exact amount of the superfluous gas taken care of in thisway is controlled by the adjustable area of the opening between thestack and the main collecting flue. In most plants it will be suflicientthat the stack should have large enough capacity to carry off an amountof I. I gas which normally passes through a single boiler. It is notnecessary, utilizin my invention, to provide separate stacks or each-ofthe kilns as is the usual practice, and since the PATENT? F housings orchambers at the ends of the,

kilns do not have to carry the load or weight of separate stacks,they-can be placed over and supported by the main collectin flue, andthis is one of the features of t e inventlon.

Another object which I have in-view is based on the fact that, asheretofore constructed, the common flue, which, for structural reasons,is'made relatively high and narrow, receives the gases from the kilnsthrough aside wall and, as the gases are mov ng with considerablerapidity and the opposlte wall is comparatively close to the point ofentrance for the gases, objectionable eddies occur which interfere tosome extent with the desired draft conditions. My method for diminishingthis objectionable feature of the ordinary lant isto introduce the gasesfrom the kilns into the top of thecommon flue so that their momentum canbe expanded through the longer distance between the top and bottom ofthe flue and thus give rise to less draft inequalitles. The dust carriedby the gases, which otherwise would be in part dropped on the floor ofthe housing, passes down throu h the draft openings into the top of themam flue and is deposited in the bottom of this main flue where it canbe easily removed. A small light stack can beput on the top sol of thesehousings with a damper between the housing and the stack for use whenthe kiln is bein first started up, or for producing a flow 0 air throughthe kiln when work is being done on the lining, but in all regular.conditions of operation this stack is unnecessary and its use would beconfined to the purposes stated. Other advantages incident to theintroduction of the gases through the top of the flue are that itenables me to compact the plant and make the housings into which thefurnaces open more accessible, and the furnaces more accessible throughthe housings, by erecting these housing chambers on top of the Patent,No. 1,393,738 of October 18, 1911,

mally existing in the flue, and this, construction and method of oeration, resultin that is, should be so throttled as to make the ressuredro between the housing and the no greater t an the pressuredrop-nornatufally in a high spee of flow throng the ports, makes theadvantage derived from the introduction of the gases into the top of theflue more manifest.

-My invention will be best understood as vdescribed in connection withthe drawings ".inwhich.:

. Fi re 1 is a plan view of a plant embodymg my improvements and adaptedto mynewrmethods of operation, shown partly on sections 1-1 of Fig. 2.

Figure 2 is an elevation shown for. the

most part onthe section line 2-2 of Fig. l,

' anding Fig. 2. A, indicate rotary;1

which any number can e Figurefiis a section on the line of v embodied inthe plant. "B is the common waste heat flue which is usuallyconstructed, as shown, of relativel considerable height in relation toits brea tli'. B is a hopper shaped bottom for the flue from whichspouts B leadto a conveyor at B -built under the flue'B. At spacedintervals .are the kiln housings G hav in their-front wall openin s C"which register with'the ends of the 1111118 and are usually surroundedby some sealing device diagrammatically indicated at C The opposite orrearwalls C shown asprovided with a pipe open1ng C* of these housingsare through which a thermo-couple can be mtroduced and with inspectionopenlngs lying directly opposite to themouth of the kiln pressure dropthrough these ports somewhat inexcess of the pressure loss in theconnecting flue. D, D, 1n-

- dicate stacks, damper controlled, by which at will the gases from thekiln can be thrown off from the housing without passing into the commonflue. E, E, are ports leadmg from the flue B into the waste heat boilersindicated at F, F, and thence through economizers indicated at G, G, toovens H andstacks I. J is an opening leading from-the common flue B to astack J vJ indicating a guideway for a damper by which the opening J canbe regulated or closed at will. The stack J 2 should be of such heightthat when 6 filled with hot gases from the .flue it will create asuction equal to that normally existing in the flue'B while the capacityof the stack J; should be such that it can,

1 in case of emergency, carry-off such amount through their housing 0over and above that as the kilns deliver to the flue cement kilns ofwhich the boilers in use are capable of drawing from the flue. Ordinarilas I have noted, it willbe' sufficient that t 'e stack J 2 should havecapacity to carry off the gases normally passin through one of theboilers.

Having now escribed my invention what I claim as new and desire tosecure by Letters Patent, is:

a 1. Themethod of maintaining even draft.

conditions in a plant consisting of one or more industrlal furnaces, acommon flue into which they deliver their gases and a plurality of wasteheat boilers connected to utilize gases from'said flue and having draftfans for'maintaininga proper draft,

which consists in providing an outlet for gases from the flue other thanthose through the boilers and fans, and maintaining in said outlet asuction equal to the suction nor 'mally .exlstmg in the common flue.

2. The method of maintaining even draft conditions in a plant consistingofone or more industrial furnaces, a high and relatively narrow commonflue into which they deliver their gases and a plurality of waste heatboilers connected to utilize gases from the flue and having draft fansfor maintaining a proper draft, which consists in introducing the gasesfrom the furnaces into the flue through the top thereof, providing anoutlet for gases from the flue other than those through the boilers andmaintaining in said outlet a suction equal to the suction normallyexisting in the'comm'on flue.

3. The method of maintaining even draft conditions in a plant consistingof one or more industrial furnaces, a high and relatively narrow commonflue into which they deliver their gases and a plurality of waste heatboilers connected to utilize gases from the flue and having draft fansfor maintaininga proper draft, which consists inintroducing the gasesfrom the furnaces into the flue through the top thereof, throttling theports through the to-p of the flue so as to make the pressure droptherein greater than that in the common flue, providing an outlet forgases from the flue other than those outlet a suction equal to thesuction normally existing in the common flue.

I 4. In a plant comprising one or mofeeim du strial furnaces, a commonflue for re iv- 'ingtheir gases and a plurality of waste enable it tocarry ofi excess gases in the flue when one ormore but not all .oftheboilers and fans are not use. I. '5. In a plant comprising one or morethrough the boilers and maintaining in'said industrial furnaces eachhaving a housing chamber into whlch the gases from the furnaces pass, acommon flue for receivmg the gases from saidchambers and a plurality ofwaste heat boilers connected to said flue, and having draft fans formaintaining a proper draft, the combination therewith of a draft stackconnected to the common flue of a height adapted to maintain a suctionin the flue and furnaces equal to that normally existing therein and acapacity which Will enable it to carry ofl excess gases in the flue whenone or more but not all of the boilers and fans are not in use and aseries of stacks connected one to each housing chamber through which thegases from the connected furnaces can be diverted at will.

6. A Waste heat using kiln plant comprising in combination a horizontalflue, housing chamber for the upper ends of the kilns erected on top ofthe horizontal flue and opening into the top of said flue through theirbottoms, rotary kilns opening into the housing chamber and Waste heatboilers connected to the flue.

7. A Waste heat using kiln plant comprising in combination a horizontalflue, housing chambers for the upper ends of the kilns erected on top ofthe horizontal flues and opening into the top of said flue through 30their bottoms, damper controlled stacks leading from each housingchamber, rotary kilns opening into the housing chamber and' waste heatboilers connected to the flue.

8. A Waste heat using kiln plant compris- 35 ing in combination ahorizontal flue, a dust conveyer for carrying off the dust from thebottom of the flue, housing chambers for the upper ends of the kilnserected on top of the horizontal flue and opening .into the 40 top ofsaid flue through their bottoms, rotary kilns opening into the housingchamber and waste heat boilers connected to the flue.

JOHN E. BELL.

